1.1 This test method measures the contact angle of a test liquid in contact with a flat specimen of a film or a paper substrate under specified test conditions. This test method may be used with any liquid of interest which is compatible with the equipment used, particularly with regard to liquid viscosity, tackiness, and vapor pressure (evaporation). This test method may be used with any substrate of interest, which can be cut to dimensions compatible with the equipment used.
1.2 For materials which sorb the test liquid under the specified test conditions, the rate of change of the contact angle as a function of time may be significant, and may be determined using procedures described in this test method. It is also possible to evaluate the sorptive properties of a surface, as the remaining liquid volume on top of the specimen surface is measured as a function of time.
1.3 The conditions required in this test method specify reagent water as the test liquid when testing papers designed to be absorbent, such as absorbent tissue grades.
1.4 Conditions are specified for the testing of a wide range of papers considered to be of low absorbance or nonabsorbent, including release papers, sized, coated, or unsized papers designed for printing, writing, wrapping, and similar tasks where the paper surface interaction with aqueous or solvent based inks or other aqueous or nonaqueous liquids is important. In such cases, test liquids other than reagent water, including writing and printing inks, or organic liquids or mixtures of organic liquids may be used as the test liquid upon prior agreement of those involved in the testing, provided the liquid is compatible with the equipment used. Where test liquids other than reagent water are used, the actual liquid used is reported.
1.5 Conditions are also specified for the testing of polymer films, polymer-coated papers, paper laminates, felt, textiles and non-wovens, using water or other fluids compatible with the equipment and important to the end-use applications of the materials tested, including gluing and printing.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.